The Histopathology Core will serve as a repository of tissues, immunohistochemical reagents and reagents for in situ hybridization studies. Human and animal tissues harvested for experimental studies will be catalogued, differentially processed (frozen samples, fixed for routine histology, processed for immunohistology and in situ hybridization studies) and stored for analyses. We have human samples dating back to 1991. In Table 1, we provide a listing of what has been collected from 2000 to present. Analytic procedures will be standardized by periodic quality control operations. New tissues (from nude mice and transgenic mice) and new reagents will be analyzed thoroughly and the data stored for future experiments. Core F will function in tight coordination with the tissue culture and molecular biology cores. Since the last competing renewal in 2000,16 peer-reviewed papers and nine abstracts published by the group have utilized the facilities and expertise provided by Core F.